1. Field
This disclosure relates to an iridium phosphorescent dendrimer, a method of preparing the iridium phosphorescent dendrimer and an electroluminescent device including the iridium phosphorescent dendrimer, and more particularly, to an iridium phosphorescent dendrimer exhibiting good self-film forming properties, a method of preparing the iridium phosphorescent dendrimer exhibiting good self-film forming properties and an electroluminescent device including the iridium phosphorescent dendrimer exhibiting good self-film forming properties.
2. Description of the Related Art
Semiconducting organic materials have attracted considerable interest as candidate materials for electronic and optoelectronic devices. Electroluminescent (“EL”) devices using semiconducting organic materials have gained popularity and are already being used in practical applications such as flat-panel displays and flexible display devices.
In particular, dendrimer light-emitting materials (DLED) may be used to provide fast response, high brightness, low driving voltage, ease of device fabrication, and good processability
Cyclometalated Ir(III) complexes including DLED show high phosphorescent efficiency.
Organic light-emitting diodes (“OLEDs”) including cyclometalated Ir(III) complexes are fabricated by repeated thermal evaporation to provide several organic layers. However, the thermal vacuum deposition process for fabricating EL devices is relatively complicated and costly. Also, doping an iridium complex into a host polymer or large molecule is disadvantageous due to phosphorescent self-quenching, phase separation and insufficient energy transfer, thereby leading to fast decay of luminescence efficiency and external quantum efficiency (“EQE”) with an increase in current density. Thus, there is a need for an iridium phosphorescent dendrimer that may be used without a host and that can form an organic layer by a solution process.